DIY Intake Manifold Gasket Change (among many other things)

[Comage]

Background

Again, I had been meaning to do a short write-up of my experience when performing a DIY intake manifold gasket change, among many other scheduled maintenance items I needed to perform on my vehicle (Toyota 2008 1ZZ-FE engine - some of you guys probably can identify what vehicle I have from the images, but please don't call me out for being cheapskate, low-SES or whatever names you can possibly think of).

Just want to share some of the lessons learnt along the way when I did this job - which online YouTube guides do not talk about (especially with regards to additional parts required)

The reason I needed to do this gasket job was because I was getting an error code P0171 "System Too Lean (Bank 1)" on my vehicle:

This error code started appearing after I had accidentally sheared off one of the intake manifold bolts (don't ask me how this happened😞

Preparing for the Job

I had ordered in all the parts online, since for some strange reason the local Toyota stockists do not seem to stock most of these parts *at all*, especially the smaller items like nuts, bolts and studs:

• Intake Manifold Gasket
• Throttle Body Gasket (since the throttle body was going to come out, aiya might as well la)
• Bolts, nuts and studs (to replace all existing ones that were aged and very much at risk of shearing off if I took it off)
• Oil Control Valve Filter (aiya might as well right?)

Dismantling the Intake Manifold

So I had rehearsed the steps many times after viewing all the YouTube tutorial videos, and was ready to start work:

1. First the engine intake air hose had to come out - and unfortunately due to age, the hose cracked as I pried it out... 😞

2. Then, the throttle body came out, but there was a strange corrosion on one of 4 bolts... (which seemed indicative of leaking coolant?)

Also, the throttle body was in a very bad state with a lot of carbon build-up:

3. Then, the fuel vapour feed hose was to come out... but it broke as I tried to wiggle it loose (!!!) 😢

More on this broken hose in the later sections...

4. I had also managed to extract the sheared-off bolt after everything was done:

5. Peeking inside each of the cylinders, they were all in bad shape (no surprises, given that my vehicle was once a PHV), but I did not want to go down the rabbit hole and start doing a lot more stuff than what was needed for this intake manifold gasket job:

6. Finally, after about 4 hours later (yes... I am just a weekend wannabe mechanic) - everything was out, and the radiator hoses clamped off when the throttle body came off:

Cleaning the Intake Manifold

Cleaning the intake manifold is easy - there's a lot of YouTube videos out there showing you how. But one thing was that I realised that I had oil collecting in my intake manifold... (hmm...):

Gasket change was done right after the intake manifold was cleaned and prepped - the old one had to be pried out (again!) and was hard as a dog's biscuit (not shown in pictures):

Cleaning the Throttle Body

Again, I won't go into much detail about this - except for the fact that after cleaning the throttle body, I realised that someone had already gotten here before me, and had done a shitty job by using a screwdriver or some sharp tool to pry open the butterfly valve (note the scratch marks!😞

Front side of throttle body - most guides online only mention cleaning this side:

The throttle body gasket was replaced as well:

Fuel Vapour Feed Hose

When I broke the fuel vapour feed hose, I called up all the stockists, and they all told me that they do not stock the vapour hose!

I even called the scrap yards, and they said the same thing too - well, quite obviously, because who wants to buy a used rubber hose that was at risk of cracking/breaking upon installation? So, since the vapour hose was a no-go, no choice la, got to order the parts online from Japan. The online websites indicated at least a 6-8 days turnaround time for the part - which was a real bummer of a downtime to incur for my car... 😞

And then a thought struck me - that this is just a rubber hose, correct?

And so, I paid a visit to the nearby hardware shop and bought a short roll of rubber hose with the closest diameter - and fashioned a makeshift hose (including migrating the existing insulation and retaining clips over from the broken hose😞

Makeshift hose was fixed in as a temporary measure while waiting for the actual vapour hose to arrive from Japan:

Oil Control Valve Filter

Also replaced the oil control valve filter, since I had already dismantled the intake manifold, making the filter easily accessible:

Out with the old filter... and in with the new:

 

Reassembly

So then everything was reassembled back together again without any further mishaps - and all bolts and nuts torqued down to specs:

Fired up the car, and voila!

Conclusion

I am still waiting for the fuel vapour feed hose to arrive from Japan - it's been 3 weeks already. But so far, so good for the makeshift hose - which to my surprise worked!

Quite exasperating also that local stockists aren't all what they seem to be (at stocking up parts) - I had asked specifically whether it's an "out of stock" problem? Or what?

The stockists all answered - we never stock this part at all - which made me wonder: How the hell do workshops repair such broken hose issues? Do they go with makeshift hoses like I did?

I did incur a bit more unexpected downtime due to the broken hose, but fortunately, my vehicle was back on the road after 3 days of downtime. Not bad actually, considering the amount of labour costs I had saved, plus all the findings I had regarding the throttle body bolts, the pooled oil in the intake manifold gasket, and the choked up cylinders (maybe for the next write-up...?)

Feel free to ask away, comment or critic as necessary, and thanks for reading this long post!

[Mkl22]

The cracked hose to the air filter box, can be left alone. Doesn’t really affect much since the air there is before the throttle body and not part of the vacuum system. 
seems like you have quite some blow by, since there is quite some oil in the intake manifold. Do you notice a drop in engine oil? Happen to know the true mileage of the vehicle? 
did you also manage to check the pcv and the and clean it? 
 

Edited May 3, 2022 by Mkl22

[Comage]

21 minutes ago, Mkl22 said:

The cracked hose to the air filter box, can be left alone. Doesn’t really affect much since the air there is before the throttle body and not part of the vacuum system. 
seems like you have quite some blow by, since there is quite some oil in the intake manifold. Do you notice a drop in engine oil? Happen to know the true mileage of the vehicle? 
did you also manage to check the pcv and the and clean it? 
 

1. Cracked air hose - yes I realised I could leave it alone... After I had ordered the part in :S

2. Drop in engine oil, yes. Last time I was topping up 1lit/mth - after fixing up a lot of gasket leaks, now it's manageable - there's still a drop in engine oil but it can last until my next oil change and not hit critically low level on the dipstick (I change engine oil every 6 months now). 

3. True mileage, I don't know. When I got it it was 98k km at 10th year... And I was the 3rd owner. I'm guessing true mileage should maybe be 1.5x that at maybe 150k km... 

4. PCV and hoses connecting to the PCV have all been changed as well right when I got this vehicle - I did it myself. 

I peeked into all the cylinders and they were in pretty bad shape actually, with a lot of charring on the valves and chambers. It's quite obvious that the previous owners did not keep up with the oil changes regularly.

This vehicle's COE is coming to an end next year... So I'm just maintaining status quo - otherwise I'd go for maybe a DIY valve/piston/o-ring/oil seal replacement.

Edited May 3, 2022 by Comage

[Mkl22]

16 minutes ago, Comage said:

1. Cracked air hose - yes I realised I could leave it alone... After I had ordered the part in :S

2. Drop in engine oil, yes. Last time I was topping up 1lit/mth - after fixing up a lot of gasket leaks, now it's manageable - there's still a drop in engine oil but it can last until my next oil change and not hit critically low level on the dipstick (I change engine oil every 6 months now). 

3. True mileage, I don't know. When I got it it was 98k km at 10th year... And I was the 3rd owner. I'm guessing true mileage should maybe be 1.5x that at maybe 150k km... 

4. PCV and hoses connecting to the PCV have all been changed as well right when I got this vehicle - I did it myself. 

I peeked into all the cylinders and they were in pretty bad shape actually, with a lot of charring on the valves and chambers. It's quite obvious that the previous owners did not keep up with the oil changes regularly.

This vehicle's COE is coming to an end next year... So I'm just maintaining status quo - otherwise I'd go for maybe a DIY valve/piston/o-ring/oil seal replacement.

Oh. Another year. Then don’t bother la. 

[Comage]

13 minutes ago, Mkl22 said:

Oh. Another year. Then don’t bother la. 

Lesson learnt: I should immediately do a tear-down of the engine for my next purchase, and rectify it straight away for my next used vehicle purchase, and not wait until the last year to do so. 

[Mkl22]

32 minutes ago, Comage said:

Lesson learnt: I should immediately do a tear-down of the engine for my next purchase, and rectify it straight away for my next used vehicle purchase, and not wait until the last year to do so. 

Surprised that you would have bought an ex PHV. If you diy can see the signs of an abused or high mileage car. 

[Gnahp]

well done 👍

this type of work is back breaking

how is your back and the thigh muscles? 😁

[Watwheels]

Wow, I think the bolt that sheared off has never been dismantled for ages. Corrosion has taken place. Should have sprayed the bolts with wd40 first and let it sit for a while before you begin. A good practice will be to apply a small layer of grease on the threads before installing back. 

Vacuum or vapour hose you can get it from hydraulic hose shops, just Google. When you are there ask for fuel line hoses. They will sell by the length in meters. Getting one meter is ok too. 

Yucks, maintenance for phv vehicles suck.

Good thing about old engine design is that they dont have an EGR system. Less one headache.

Edited May 3, 2022 by Watwheels

[Comage]

47 minutes ago, Mkl22 said:

Surprised that you would have bought an ex PHV. If you diy can see the signs of an abused or high mileage car. 

It was a chicken and egg problem Sir. For me, this car came first... And it was because of this car in it's banged-up state that I started picking up DIY works on it. 

While working on it I realised it was a PHV. Otherwise I'd be sending it to the workshop every other month for wear and tear issues. 

And no workshop (at least, mine won't) will do one-shot works on all wear and tear... Because it takes up space at the workshop, with only 1 x labour fee chargeable. 

Edited May 3, 2022 by Comage

[Heartbreakid]

Hi does the engine feel after the intake clean up compare to before?

[Colin03]

U are great bro, a DIY man

Appreciate on your brief job done

is a 100% satisfaction for u I believe 

[Mkl22]

2 hours ago, Watwheels said:

Wow, I think the bolt that sheared off has never been dismantled for ages. Corrosion has taken place. Should have sprayed the bolts with wd40 first and let it sit for a while before you begin. A good practice will be to apply a small layer of grease on the threads before installing back. 

Vacuum or vapour hose you can get it from hydraulic hose shops, just Google. When you are there ask for fuel line hoses. They will sell by the length in meters. Getting one meter is ok too. 

Yucks, maintenance for phv vehicles suck.

Good thing about old engine design is that they dont have an EGR system. Less one headache.

Sometimes with diy, you break parts and then the car is immobile. If you have another car then ok to run around to get the necessary parts. Else LL and have to take public to get the needed parts. 
can be a huge hassle. 

[Comage]

2 hours ago, Watwheels said:

Wow, I think the bolt that sheared off has never been dismantled for ages. Corrosion has taken place. Should have sprayed the bolts with wd40 first and let it sit for a while before you begin. A good practice will be to apply a small layer of grease on the threads before installing back. 

Vacuum or vapour hose you can get it from hydraulic hose shops, just Google. When you are there ask for fuel line hoses. They will sell by the length in meters. Getting one meter is ok too. 

Yucks, maintenance for phv vehicles suck.

Good thing about old engine design is that they dont have an EGR system. Less one headache.

I don't think grease should be applied to the threads before installing back the bolts! Otherwise you run the risk of the bolts coming loose after some time. The bolts itself had torque specs of 18.5Nm - so I just followed the engine repair manual (thank goodness it's a Toyota!) and torqued it back.

If the bolts that got removed has signs of threadlocker on it, I'd definitely put some back when re-installing it (unless it was touched before by some dinky workshop mechanic who didn't bother to do so when working on the vehicle). Otherwise it should be just torqued back to spec...

[Comage]

4 hours ago, Phang said:

well done 👍

this type of work is back breaking

how is your back and the thigh muscles? 😁

Damned Sir... You hit the nail on the head - my back was indeed breaking at the end of the job. 

The most difficult thing was breaking loose some of the bolts, which were clearly (over-)tightened using an air impact wrench. 

Lucky I had a variety of tools at my disposal to break those bolts loose! 

[Volvobrick]

13 minutes ago, Comage said:

Damned Sir... You hit the nail on the head - my back was indeed breaking at the end of the job. 

The most difficult thing was breaking loose some of the bolts, which were clearly (over-)tightened using an air impact wrench. 

Lucky I had a variety of tools at my disposal to break those bolts loose! 

How did you extract the broken bolt? 

[Comage]

2 hours ago, Heartbreakid said:

Hi does the engine feel after the intake clean up compare to before?

1. Before this job, whenever I go up MSCP ramps at low speeds, the whole car would sometimes shudder like the engine was gonna stall. 

After the job, this shuddering seemed to have stopped happening. Acceleration upslope is now very smooth mmgh

2. On expressways, previously if I floor the pedal, pickup would be very slow (much slower than cars of smaller cc than mine!) Now, pickup seems to be much faster and instantaneous... But apologies, I did not do any dyno testing to get the concrete numbers. 

[mersaylee]

16 minutes ago, Volvobrick said:

How did you extract the broken bolt? 

...and it was sheared instead...not to ask but am curious too...😁

[Mkl22]

12 minutes ago, Comage said:

1. Before this job, whenever I go up MSCP ramps at low speeds, the whole car would sometimes shudder like the engine was gonna stall. 

After the job, this shuddering seemed to have stopped happening. Acceleration upslope is now very smooth mmgh

2. On expressways, previously if I floor the pedal, pickup would be very slow (much slower than cars of smaller cc than mine!) Now, pickup seems to be much faster and instantaneous... But apologies, I did not do any dyno testing to get the concrete numbers. 

How much did all the parts cost in the end? I would have just replaced the intake gasket and be done. Since it is just another year or so.